;;; -*- lexical-binding: t -*-
;;
;; this file:
;;   https://dataswamp.org/~incal/emacs-init/grad.el

(require 'cl-lib)
(require 'color)

(defun grad-box (w h &optional char)
  (or char (setq char ?\s))
  (let ((gcols (cl-concatenate 'list
                 (reverse (color-gradient '(0.1  0.1  0.1)  '(0.1 0.7 1.0) (* (/ h 2) w)))
                          (color-gradient '(0.05 0.05 0.05) '(0.1 0.9 0.1) (* (/ h 2) w))
                               )))
    (goto-char (point-min))
    (cl-loop
     for c in gcols do
     (let ((str (char-to-string char)))
       (insert (propertize str 'face
                           (list :weight 'bold :foreground (color-rgb-to-hex
                                                            (nth 0 c)
                                                            (nth 1 c)
                                                            (nth 2 c))))))
     (when (= (current-column) w)
       (insert "\n")))))

(defun grad-box-buf (c)
  (interactive)
  (let ((buf (get-buffer-create "*grad*")))
    (with-current-buffer buf
      (erase-buffer)
      (grad-box 78 28 c)
      (goto-char (point-min)))
    (pop-to-buffer buf)))

;; (eval-buffer)
;; (grad-box-buf ?-)

(provide 'grad)